A Single Bang, Knock, Clunk or Clang
Such sounds are usually caused by a phenomenon called 'water hammer.' Water hammer doesn't accompany flowing water, so if your sound occurs while water is running, it isn't water hammer.
Water hammer happens when you turn OFF a water flow suddenly (like a dishwasher, a clothes washer, a toilet or even closing a hand faucet suddenly. Shutting off the flow suddenly sends a pressure or shock wave down the water line through the water shocking the pipes and creating the 'hammer' noise. These shock waves travel faster than the speed of sound and can exert very great instantaneous pressures. Over time, water hammer can damage pipes, valves and eventually weaken pipe joints.
Most modern homes have devices called water hammer arresters ( they're called various things such as air chamber, air cushion, water capacitor, etc.) . They are air filled chambers connected to the plumbing that let the pressure wave dissipate harmlessly into a cushion of air. If your banging has been happening forever you may not have one.
Sometimes these arresters become waterlogged. Try this. Turn off the water to the house at the entry. Find the lowest faucet in your house--often this is an outdoor garden hose faucet--open this faucet and then open a few of the indoor faucets at high locations such as upstairs or at a wet bar and let the low faucet drain for 5 minutes or until it stops dripping, whichever takes longer. Close all the faucets and turn the main back on. Note: When you first start using water again there will be air in the lines and it may spit and sputter with some vigor.